通過Dapr實現一個簡單的基於.net的微服務電商系統(十八)——服務保護之多級快取

    public class L1Cache : IL1CacheServiceFactory
    {
        private readonly IMemoryCache memoryCache;
        public L1Cache(IMemoryCache memoryCache)
        {
            this.memoryCache = memoryCache;
        }
        public T Get<T>(string key)
        {
            Console.WriteLine($"L1快取被調用,KEY={key},value{(memoryCache.Get<T>(key) == null ? "不存在" : "存在")}");
            return memoryCache.Get<T>(key);
        }

        public bool Set<T>(string key, T value, int expireTimeSecond = 0)
        {
            return memoryCache.Set(key, value, DateTimeOffset.Now.AddSeconds(expireTimeSecond)) != null;
        }
    }

　　二級快取實現：

    public class L2Cache : IL2CacheServiceFactory
    {
        private readonly IStateManager stateManager;
        public L2Cache(IStateManager stateManager)
        {
            this.stateManager = stateManager;
        }
        public async Task<T> GetAsync<T>(string key)
        {
            var cache = await stateManager.GetState(new L2CacheStore(key),typeof(T));
            Console.WriteLine($"L2快取被調用,KEY={key},value{(cache == null ? "不存在" : "存在")}");
            if (cache != null)
                return (T)cache;
            return default(T);
        }

        public async Task<bool> SetAsync<T>(string key, T value, int expireTimeSecond = 0)
        {
            var resp = await stateManager.SetState(new L2CacheStore(key, value, expireTimeSecond));
            return resp != null;
        }
    }
    internal class L2CacheStore : StateStore
    {
        public L2CacheStore(string key, object data, int expireTimeSecond = 0)
        {
            Key = $"DarpEshopL2CacheStore_{key}";
            this.Data = data;
            this.TtlInSeconds = expireTimeSecond;
        }
        public L2CacheStore(string key)
        {
            Key = $"DarpEshopL2CacheStore_{key}";
        }
        public override string Key { get; set; }
        public override object Data { get; set; }
    }

　　接著我們將這兩個實現注入到我們的webapplication里並在middleware里通過use啟動它：

builder.Services.AddMemoryCache();
builder.Services.InjectionCached<L1Cache, L2Cache>();
//......
var app = builder.Build();
app.UseCached();
//......
await app.RunAsync();

　　最後我們在AccountQueryService.cs里對GetMockAccount添加對應的快取註解：

        [SystemCached]
        public async Task<ApiResult> GetMockAccount()
        {
            Console.WriteLine("GetMockAccount被調用");
            //......
        }

　　*默認註解參數為int expireSecond = 60, int timeOutMillisecond = 5000, SystemCachedType cachedType = SystemCachedType.Method。其中expireSecond代表你想要的快取的時間，單位為秒，timeOutMillisecond是指在框架嘗試請求二級快取時的超時等待時長，單位毫秒。cachedType代表快取類別，SystemCachedType.Method代表僅使用方法作為快取key，SystemCachedType.MethodAndParams代表會根據方法名+參數來實現更加細化的快取key

　　最後啟動我們的項目，現在通過postman來訪問這個介面，列印日誌如下：